but believe it or not, some people are betting against you. here's abc's matt gutman. >> three, two, one. happy new year! >> reporter: no sooner as the new year's ball dropped and up popped jessica simpson. one of is very first ads of the new year. >> because when a weight loss program is built for human nature, you can expect amazing. >> reporter: our resolutions, more personal. 40% of americans make these promises. >> i was going to try to be nicer to my brother. >> take more risks in life. >> reporter: by some accounts, a third of these promises are broken before the end of january. not so amazing. the perennial top two resolutions are increasing exercise and decreasing your weight. it's a $66 billion industry. do they continue with the programs they start? >> there are some people that do, but there's a group that's consistently inconsistent. >> reporter: market analysts show that gym memberships peak in monday and by march they plummet. 80% of new members become no members after just eight weeks. >> it's a lifestyle change. i hope i can m